Sofa



FIG. 1 is a perspective view of my sofa;

FIG. 2 is a front view thereof;

FIG. 3 is a right side view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a top view thereof;

FIG. 6 is a rear view thereof; and,

FIG. 7 is a close-up front view of the ornament at the top center portion of my sofa.

The broken lines shown in the drawings are for environmental purposes only and form no part of the claimed design. 

The ornamental design for a sofa, as shown and described. 